GABA-DA interactions will be further evaluated by studying the influence of drugs on both DA and GABA turnover. gaBA turnover will be measured by studying the increase in GABA levels after inhibition of the GABA transaminase with the help of aminooxyacetic acid or glutamatehydrazide. Possible role of Substance P in the control of he acending DA pathways will be evaluated as well as the possibility that a number of presumable gabergic drugs may block Substance P receptos. A number offantipsychotic compounds will be studied for their ability to block cortical DA receptors.